The present invention relates to a new and improved manual post hole digger. The improved manual post hole digger permits the user to more conveniently produce a vertical hole with an essentially constant hole diameter through the length of the hole, enabling the user to dig deep holes.
A common type of manual post hole digger is the clamshell post hole digger. Previously known clamshell post hole diggers typically comprise a pair of sharpened shovel blades mounted on pivotally connected elongated handles. The post hole digging is accomplished by thrusting the blades into the ground then spreading the handles apart forcing the shovel blades together gripping the soil. The soil is then removed from the hole and dumped to the side. This process is repeated until a hole of the desired depth is attained.
The principal problem with this type of clamshell post hole digger is, as the hole is dug deeper the handles cannot be spread sufficiently far apart to grip the soil. Therefore, the diameter at the hole opening must be increased as the depth of the hole is increased.
Many attempts have been made to design clamshell post hole diggers which can dig a deep hole without the need to increase the diameter at the opening of the hole. Such diggers are provided by: Luck (U.S. Pat. No. 5,669,648), Alienate (U.S. Pat. No. 5,478,128), Robinson (U.S. Pat. No. 5,427,424), Burnham (U.S. Pat. Nos. 5,320,363, 5,273,331), Arens (U.S. Pat. No. 2,710,765), Rice (U.S. Pat. No. 2,654,626), Sonnenberg (U.S. Pat. No. 2,435,473), Loos, el al. (U.S. Pat. No. 2,230,498), Mayeda, et al. (U.S. Pat No. 2,028,680), McDowell (U.S. Pat. No. 1,888,929) and Theriot (U.S. Pat. No. 1,706,332). These devices are complex and difficult to operate. The devices often contain numerous parts that become worn and damaged from the soil and debris.
There remains a need for a low cost, simply built, reliable, and easy to use clamshell post hole digger.